A multichannel optical transceiver having a Vertical Cavity Surface Emitting Laser diode, such as a VCSEL (Vertical Cavity Surface Emitting Laser) or a photodiode (photodetector), has been known. In an optical module such as the foregoing multichannel optical transceiver, the light entry surface or the light exit surface of a Vertical Cavity Surface Emitting Laser diode is parallel to the mounting substrate, and therefore light enters or exits perpendicularly to the mounting substrate. When reducing the size or thickness of such an optical module, it is preferable that optical fiber (optical fiber array) be disposed parallel to the mounting substrate. In this case, an end face of the optical fiber is substantially perpendicular to the light entry surface or the light exit surface of the Vertical Cavity Surface Emitting Laser diode. For this reason, it is necessary to bend the path (optical path) of light perpendicularly entering or exiting the light entry surface or the light exit surface of the Vertical Cavity Surface Emitting Laser diode mounted on the substrate at about 90 degrees and to optically connect the optical fiber and the Vertical Cavity Surface Emitting Laser diode. Japanese Laid-open Patent Publication No. 2005-115346 proposes a technique in which an optical waveguide structure having an optical waveguide on a surface curved substantially at right angle is used in order to sharply bend the path of light in a narrow space in an apparatus such as an optical transceiver, and light entering or exiting a Vertical Cavity Surface Emitting Laser diode is guided along the curved surface and coupled to an optical fiber array.
Japanese Laid-open Patent Publication No. 2008-158445 discloses a method for uniformly filling with liquid core without mixing air bubbles in the manufacturing of an optical waveguide structure.
In the manufacturing of an optical waveguide structure of Japanese Laid-open Patent Publication No. 2008-158445, a clad film needs to be disposed on a curved surface so as to be coplanar with the end face where the optical path is exposed.